1. Technical Field
The present invention relates to a double-sided receipt printing method and a double-sided receipt printer that produce receipts by printing on both sides of the receipt paper using two printheads disposed with a gap therebetween in the paper conveyance direction and then cutting the paper after printing is completed. More specifically, the invention relates to a double-sided receipt printing method and double-sided receipt printer that can reduce paper wasted by white space formed at the leading end of the receipt without needing to reverse the paper in the conveyance direction.
2. Related Art
Printers for producing receipts are commonly used in supermarkets and other retail stores. These printers include duplex printers that can print on both sides of the paper in order to use paper more efficiently.
Japanese Unexamined Patent Appl. Pub. JP-A-2007-320188 teaches technology enabling a duplex printer to split the print data between the front and back sides of the paper for fast printing.
Japanese Unexamined Patent Appl. Pub. JP-A-2009-123028 teaches technology for shortening the length of the receipt by dividing the transaction information printed on the receipt between both sides of the paper and printing to areas other than where the store information is printed.
The cutter for cutting the paper after printing, a first printhead that prints on one side of the paper, and a second printhead that prints on the other side of the paper are disposed in this order with a specific gap therebetween from the downstream end of the paper conveyance direction in the duplex printers described above. As a result, the cutter and the upstream side printhead are physically separated a specific distance, and white space equal to this distance is formed at the leading end of the receipt on the side printed by the upstream side printhead after the paper is cut unless some special action is taken.
The paper could be reversed in the paper feed direction and moved to a specific position before printing starts to reduce this paper waste, but this method requires time to move the paper and some mechanical means of preventing paper jams, and thus has problems.
A JP-A-2007-320188 is silent about solving this problem. JP-A-2009-123028 describes the white space created by the distance between the two printheads, but does not address white space created by the distance between the cutter and the printheads.